1. Field of the Invention
The present invention relates to a method of rolling finished sections from a preliminary section by means of an arrangement which operates in a reversing operation and includes a compact rolling group composed of a first universal stand on an entry side, a second universal stand on an exit side and an intermediate upsetting stand arranged between the first and second universal stands, wherein a preliminary rolling group composed of two or more roll stands and having a free rolling stock run-out is arranged in front of the compact rolling group and transversely offset and parallel to the rolling line of the compact rolling group and a transverse shifting unit arranged between the two rolling lines is arranged in front of the compact rolling group.
2. Description of the Related Art
In known methods and in roll stand arrangements operated according to these methods, blooms produced, for example, by a continuous casting plant are supplied to an intermediate storage in which they are cooled to room temperature, the quality of the blooms is evaluated and, after again heating the blooms to rolling temperature, the blooms are rolled into rails in the roll stand arrangement. After heating to rolling heat, the block-shaped blooms are preshaped in a preliminary rolling procedure in at least one two-high reversing stand, however, usually in two such stands. Finish rolling also took place in three-high reversing stands or two-high reversing stands; however, recently finish rolling is carried out more frequently in universal stands.
It has also been proposed in the past to carry out this shaping process in a fully continuously operating roll stand plant with the appropriate large number of roll stands and the drives thereof.
In all these methods, it is attempted to produce rails in rolling lengths which are as long as possible and to conduct these long rolling lengths as much as possible at rolling heat through head hardening or tempering plants or other heat treatment plants, wherein the rails treated in this manner were subsequently cooled, straightened, the quality evaluated and cut to length.
These known methods have the following disadvantages:
The large number of shaping passes required for preliminary rolling requires large reversing stands because of the large lengths of the roll bodies required for the large number of shaping passes; this also means that the rolls themselves are expensive, and complicated manipulating devices for introducing the rolling stock into the various passes are required. The long rolling lengths result in relatively long times required for the reversing rolling operation and, consequently, do not make it possible that such plants are operated in the same operating cycle as a continuous casting plant. For this reason, it is in such a case always necessary to provide a relatively large intermediate storage if a combined operation between continuous casting plant and rolling plant is to be carried out.
Because of the large number of shaping passes, at least six to eight roll stands with the drives thereof are required for fully continuous rolling. This results in correspondingly high investment costs, high costs for the large number of rolls and for the exchange and refinishing of the rolls. Moreover, when carrying out this continuous preliminary rolling and an also continuous finish rolling, different temperatures over the rolling length cannot be avoided, wherein these different temperatures produce so-called temperature wedges between the beginning and the end of the rolling length caused by the relatively slow entry speed into the first stand of the rolling train. These temperature wedges must be compensated or regulated in order to meet the requirements of the rolling stock which are required for the head hardening or tempering plants or the heat-treatment plants.
It is frequently required to combine a production of a small number of rails with the production of girders. The above-described conventional rail rolling methods can only be realized with a very large number of additional devices when using the known, above-mentioned plants for rolling finished sections from a preliminary section which all operate in a combined operation with a continuous casting plant, i.e., without a conventional reversing preliminary stand.